Compressed Long Range Physical Layer Protocol Data Unit (PPDU)

This application is a continuation of International Application No. PCT/US2025/033733, filed Jun. 16, 2025, which claims the benefit of U.S. Provisional Application No. 63/662,434, filed Jun. 21, 2024, all of which are hereby incorporated by reference in their entireties.

Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings.

1 FIG. illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

2 FIG. is a block diagram illustrating example implementations of a station (STA) and an access point (AP).

3 FIG. illustrates a non-High Throughput (non-HT) Physical Layer Protocol Data Unit (PPDU), a High Throughput (HT) mixed PPDU, and a Very High Throughput (VHT) PPDU.

4 FIG. illustrates a High Efficiency (HE) Single User (SU) PPDU, an HE Multi-User (MU) PPDU, and an HE Extended Range (ER) SU PPDU.

5 FIG. illustrates an Extremely High Throughput (EHT) Multi-user (MU) PPDU.

6 FIG. illustrates an example universal signal (U-SIG) field which may be used in an extended range (ER) PPDU.

7 FIG. illustrates an example management frame which may be used as an action frame.

8 FIG. illustrates a Link Measurement Request frame.

9 FIG. illustrates an example trigger frame.

10 FIG. illustrates an example Common Info field.

11 FIG. illustrates an example of using a trigger-based (TB) PPDU.

12 FIG. illustrates a non-HT Short Training field (L-STF) and a non-HT Long Training field (L-LTF).

13 FIG. illustrates an example extended long range (ELR) PPDU.

14 FIG. illustrates a legacy preamble that may be used in an ELR PPDU.

15 FIG. illustrates an example ELR PPDU according to an embodiment.

16 FIG. 15 FIG. illustrates an example that highlights a potential problem that may arise using the example ELR PPDU of.

17 FIG. illustrates an example of a procedure using an ELR PPDU according to an embodiment.

18 FIG. illustrates an example of a procedure using an ELR PPDU according to an embodiment.

19 FIG. illustrates an example ELR field that may be used according to embodiments.

20 FIG. illustrates an example process according to an embodiment.

21 FIG. illustrates another example process according to an embodiment.

In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and/or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. After reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments may not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a station, an access point, a radio environment, a network, a combination of the above, and/or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and/or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

In this disclosure, “a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of”, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of” provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, may be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and/or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and/or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.

1 2 1 2 1 2 If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B={STA, STA} are: {STA}, {STA}, and {STA, STA}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing/using” (or equally “employing/using at least”) is indicative that the phrase following the phrase “employing/using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and/or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state.

In this disclosure, parameters (or equally called, fields, or Information elements: IEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages/frames comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages/frames but does not have to be in each of the one or more messages/frames.

Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features.

Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g., hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, MatLab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEW MathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

1 FIG. 1 FIG. 100 102 102 110 120 130 illustrates example wireless communication networkin which embodiments of the present disclosure may be implemented. As shown in, the example wireless communication networks may include an Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WLAN) infra-structure network. WLAN infra-structure networkmay include one or more basic service sets (BSSs)andand a distribution system (DS).

110 1 110 2 110 1 104 1 106 1 110 2 104 2 106 2 106 3 BSS-and-each includes a set of an access point (AP or AP STA) and at least one station (STA or non-AP STA). For example, BSS-includes an AP-and a STA-, and BSS-includes an AP-and STAs-and-. The AP and the at least one STA in a BSS perform an association procedure to communicate with each other.

130 110 1 110 2 130 150 150 104 1 104 2 130 DSmay be configured to connect BSS-and BSS-. As such, DSmay enable an extended service set (ESS). Within ESS, APs-and-are connected via DSand may have the same service set identification (SSID).

102 102 108 140 140 130 102 108 1 FIG. WLAN infra-structure networkmay be coupled to one or more external networks. For example, as shown in, WLAN infra-structure networkmay be connected to another network(e.g., 802.X) via a portal. Portalmay function as a bridge connecting DSof WLAN infra-structure networkwith the other network.

1 FIG. The example wireless communication networks illustrated inmay further include one or more ad-hoc networks or independent BSSs (IBSSs). An ad-hoc network or IBSS is a network that includes a plurality of STAs that are within communication range of each other. The plurality of STAs are configured so that they may communicate with each other using direct peer-to-peer communication (e.g., not via an AP).

1 FIG. 106 4 106 5 106 6 112 1 106 7 106 8 112 2 For example, in, STAs-,-, and-may be configured to form a first IBSS-. Similarly, STAs-and-may be configured to form a second IBSS-. Since an IBSS does not include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

A STA as a predetermined functional medium may include a medium access control (MAC) layer that complies with an IEEE 802.11 standard. A physical layer interface for a radio medium may be used among the APs and the non-AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit/receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term “user” may be used to denote a STA participating in uplink Multi-user Multiple Input, Multiple Output (MU MIMO) and/or uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.

A physical layer (PHY) protocol data unit (PPDU) may be a composite structure that includes a PHY preamble and a payload in the form of a PLCP service data unit (PSDU). For example, the PSDU may include a PHY Convergence Protocol (PLCP) preamble and header and/or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel (channel formed through channel bonding), the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or “legacy preamble”) and a non-legacy portion (or “non-legacy preamble”). The legacy preamble may be used for packet detection, automatic gain control and channel estimation, among other uses. The legacy preamble also may generally be used to maintain compatibility with legacy devices. The format of, coding of, and information provided in the non-legacy portion of the preamble is based on the particular IEEE 802.11 protocol to be used to transmit the payload.

A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax and/or 802.11be standard amendments may be transmitted over the 2.4 GHz, 5 GHZ, and/or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be formed through channel bonding. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHZ, 80 MHz, 160 MHz, or 520 MHz by bonding together multiple 20 MHz channels.

2 FIG. 2 FIG. 200 210 260 210 220 230 240 260 270 280 290 220 270 230 280 240 290 is a block diagramillustrating example implementations of a STAand an AP. As shown in, STAmay include at least one processor, a memory, and at least one transceiver. APmay include at least one processor, a memory, and at least one transceiver. Processor/may be operatively connected to memory/and/or to transceiver/.

220 270 210 260 220 270 Processor/may implement functions of the PHY layer, the MAC layer, and/or the logical link control (LLC) layer of the corresponding device (STAor AP). Processor/may include one or more processors and/or one or more controllers. The one or more processors and/or one or more controllers may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a logic circuit, or a chipset, for example.

230 280 230 280 230 280 220 270 230 280 220 270 220 270 230 280 220 270 Memory/may include a read-only memory (ROM), a random-access memory (RAM), a flash memory, a memory card, a storage medium, and/or other storage unit. Memory/may comprise one or more non-transitory computer readable mediums. Memory/may store computer program instructions or code that may be executed by processor/to carry out one or more of the operations/embodiments discussed in the present application. Memory/may be implemented (or positioned) within processor/or external to processor/. Memory/may be operatively connected to processor/via various means known in the art.

240 290 240 290 210 260 210 260 210 260 240 290 Transceiver/may be configured to transmit/receive radio signals. In an example, transceiver/may implement a PHY layer of the corresponding device (STAor AP). In an example, STAand/or APmay be a multi-link device (MLD), that is a device capable of operating over multiple links as defined by the IEEE 802.11 standard. As such, STAand/or APmay each implement multiple PHY layers. The multiple PHY layers may be implemented using one or more of transceivers/.

3 FIG. 310 320 330 illustrates a non-High Throughput (non-HT) PPDU, a High Throughput (HT) mixed mode PPDU, and a Very High Throughput (VHT) PPDU.

310 310 310 3 FIG. Non-HT PPDUmay be used by STAs conforming to the IEEE 802.11a standard amendment. As shown in, non-HT PPDUincludes a non-HT Short Training field (L-STF), a non-HT Long Training field (L-LTF), a non-HT Signal field (L-SIG), and a Data field. The L-STF, L-LTF, and L-SIG form a 20 us preamble of non-HT PPDU.

310 310 310 310 The L-STF may be used by a receiver of non-HT PPDUto synchronize with the carrier frequency and frame timing of a transmitter of non-HT PPDUand to adjust the receiver signal gain. The L-LTF may be used by the receiver of non-HT PPDUto estimate channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in both the L-SIG and the Data fields of non-HT PPDU.

310 The L-SIG contains parameters needed to demodulate the Data field, which contains a payload of non-HT PPDU. The L-SIG may be equalized using the channel coefficients estimated using the L-LTF and demodulated to obtain the demodulation parameters of the Data field. The Data Field includes one or more symbols each having a duration of 4 μs, where 3.2 μs carry symbol information and 0.8 μs carry a Guard Interval (GI).

310 For non-HT PPDUs, the only supported bandwidth is 20 MHz, which is divided into 64 subcarriers. As such, non-HT PPDUmay be encoded using a subcarrier spacing of 20 MHz/64 or 312.5 kHz.

320 320 320 HT mixed mode PPDUmay be used by STAs conforming to the IEEE 802.11n standard amendment. HT mixed mode PPDUcan support MIMO to up to 4 spatial streams, which enhances spectral efficiency four folds. HT mixed mode PPDUhas a minimum preamble duration of 35.6 μs, which may increase depending on the number of spatial streams carried by the PPDU.

3 FIG. 320 As shown in, HT mixed mode PPDUincludes an L-STF, an L-LTF, an L-SIG, an HT Signal field (HT-SIG) field, an HT Short Training field (HT-STF) field, one or more HT Long Training field (HT-LTF), and a data field. The HT-LTF and data fields include of one or more symbols each having a duration of 3.6 μs or 4 μs. In both cases, 3.2 μs carry symbol information while the remaining 0.4 μs or 0.8 μs carry a GI. The 0.4 μs long GI is called short GI while the 0.8 μs long GI is called regular or normal GI.

For HT mixed mode PPDUs, two bandwidths, 20 MHz and 140 MHz, may be supported. When the PPDU bandwidth is 20 MHz, the band is divided into 64 subcarriers. When the PPDU bandwidth is 140 MHz, the band is divided into 128 subcarriers. In both cases, subcarrier spacing of 312.5 kHz is maintained.

330 330 330 330 VHT PPDUmay be used by STAs conforming to the IEEE 802.11ac standard amendment. VHT PPDUcan support MIMO transmission to up to 8 spatial streams, which enhances spectral efficiency eight folds. VHT PPDUhas a minimum preamble duration of 39.6 μs, which may increase depending on the number of spatial streams carried by VHT PPDU.

3 FIG. 330 330 As shown in, VHT PPDUincludes an L-STF, an L-LTF, an L-SIG, a VHT Signal A field (VHT-SIG-A), a VHT Short Training field (VHT-STF), one or more VHT Long Training field (VHT-LTF), a VHT Signal B field (VHT-SIG-B), and a Data field. The VHT-LTF and Data fields of VHT PPDUinclude one or more symbols each having a duration of 3.6 μs or 4 μs. In both cases, 3.2 μs carry symbol information while the remaining 0.4 μs or 0.8 μs carry of the GI. The 0.4 μs long GI is called the Short GI while the 0.8 μs long is called regular or normal GI.

For VHT PPDUs, four bandwidths, 20 MHz, 40 MHz, 80 MHz, and 160 MHz, may be supported. When the PPDU bandwidth is 20 MHz, the band is divided into 64 subcarriers. When the PPDU bandwidth is 40 MHz, the band is divided into 128 subcarriers. When the PPDU bandwidth is 80 MHz, the band is divided into 256 subcarriers. When the PPDU bandwidth is 160 MHz, the band is divided into two 256-subcarrier 80 MHz bands. In all cases, a subcarrier spacing of 312.5 kHz is maintained.

4 FIG. 410 420 430 410 420 430 illustrates a High Efficiency (HE) Single User (SU) PPDU, and an HE Multi-User (MU) PPDU, and an HE Extended Range (ER) SU PPDU. HE SU PPDU, HE MU PPDU, and HE ER SU PPDUmay be used by STAs conforming to the IEEE 802.11ax standard amendment.

410 330 410 HE SU PPDUsupports higher spectral efficiency compared to VHT PPDUdue to increased subcarrier spacing and higher order modulation support. HE SU PPDUhas a minimum preamble duration of 44 μs.

4 FIG. 410 As shown in, HE SU PPDUincludes an L-STF, an L-LTF, an L-SIG, a Repeated L-SIG (RL-SIG), an HE Signal A field (HE-SIG-A), an HE Short Training field (HE-STF) field, one or more HE Long Training field (HE-LTF), a Data field, and a PE field.

410 420 330 420 410 420 420 420 420 Similar to HE SU PPDU, HE MU PPDUsupports higher spectral efficiency compared to VHT PPDU. HE MU PPDUalso supports OFDMA. Due to denser subcarrier spacing (as in HE SU PPDU), HE MU PPDUallows for payloads of multiple users to be multiplexed in the frequency domain in the Data field. HE MU PPDUsupports multiplexing the payload of up to 9 μsers in a single 20 MHz band. HE MU PPDUhas a minimum preamble duration of 47.2 μs, which may increase depending on the number of spatial streams carried by HE MU PPDU.

4 FIG. 420 410 420 420 As shown in, HE MU PPDUincludes an L-STF, an L-LTF, an L-SIG, an RL-SIG, an HE-SIG-A, an HE Signal B Field (HE-SIG-B), an HE-STF field, one or more HE-LTF field, a Data field, and a PE field. It is noted that compared to HE SU PPDU, HE MU PPDUfurther includes HE-SIG-B. HE-SIG-B contains indications per STA of RU allocations. A STA may use the indications in HE-SIG-B to locate its payload in HE MU PPDU.

410 420 For HE SU PPDUand HE MU PPDU, the GI portion of the HE-LTF and Data field may be one of one of 0.8 μs, 1.6 μs, and 3.2 μs. An AP or STA may use a suitable GI duration depending on the channel conditions or capability of the target STA or AP.

410 420 410 420 410 420 For both HE SU PPDUand HE MU PPDU, the information portion of the HE-LTF may be one of 3.2 μs, 6.4 μs, or 12.8 μs. Depending on the information portion duration, a subcarrier spacing of the HE-LTF may be one of: 312.5 kHz if the information potion is 3.2 μs, 156.25 kHz if the information portion is 6.4 μs, and 78.125 kHz if the information portion is 12.8 μs. Unlike the HE-LTF, the information portion of the Data field for both HE SU PPDUand HE MU PPDUis always 12.8 μs. Hence, a subcarrier spacing of the Data field is always 78.125 kHz corresponding to the duration of the information portion being 12.8 μs. When a 3.2 μs or 6.4 μs long HE-LTF is used by a transmitting STA to transmit HE SU PPDUor HE MU PPDU, a receiving STA is required to interpolate the channel estimates to a subcarrier spacing resolution of 78.125 kHz to match the subcarrier spacing of the Data field.

4 FIG. 430 410 430 410 As shown in, HE ER SU PPDUincludes an L-STF, an L-LTF, an L-SIG, an RL-SIG, an HE-SIG-A, an HE-STF, one or more HE-LTF, a Data field, and a PE field. It is noted that compared to HE SU PPDU, HE ER SU PPDUhas an HE-SIG-A that is duplicated in the time domain (16 μs long instead of 8 μs long in HE SU PPDU). As such, both L-SIG (duplicated using RL-SIG) and HE-SIG-A are sent in duplicates, which allows a receiving STA to combine the two copies to increase the energy of the received signal. This results in an extended range of reception and increases transmission reliability between the transmitting STA and the receiving STA.

5 FIG. 510 510 410 420 510 410 illustrates an Extremely High Throughput (EHT) MU PPDU. EHT MU PPDUsupports OFDMA up to a bandwidth of 320 MHz. EHT MU PPDUcan improve spectral efficiency due to support of a higher order modulation compared to other PPDUs (e.g., HE SU PPDUand HE MU PPDU) while supporting the same number of spatial streams. EHT MU PPDUhas a minimum preamble duration of 47.2 μs, which may increase depending on the number of spatial streams carried by EHT MU PPDU.

5 FIG. 510 510 As shown in, EHT MU PPDUincludes an L-STF, an L-LTF, an L-SIG, an RL-SIG, a Universal Signal field (U-SIG), an EHT Signal field (EHT-SIG), an EHT Short Training Field (EHT-STF), one or more EHT Long Training fields (EHT-LTF), a Data field, and a PE field. It is noted that according to the IEEE 802.11be standard amendment, EHT MU PPDUmay be used by a transmitting STA for both SU and MU transmissions.

510 The U-SIG is intended to ensure forward compatibility of EHT MU PPDU. This means that any future PPDUs that are backward compatible to IEEE 802.11be will contain the same U-SIG field and interpretation. Because of this, IEEE 802.11be STAs will be able to understand at least in part a PPDU developed in a future amendment.

510 The EHT-SIG contains indications per STA of resource unit (RU) allocations. A STA may use the indications in the EHT-SIG to locate its payload in EHT MU PPDU.

510 The GI portion of the EHT-LTF and Data fields of EHT MU PPDUmay be one of: 0.8 μs, 1.6 μs, or 3.2 μs. An AP or STA may use a suitable GI duration depending on the channel conditions or capability of the target STA or AP.

410 410 The information portion of the EHT-LTF may be one of 3.2 μs, 6.4 μs, or 12.8 μs. Depending on the information portion duration, a subcarrier spacing of the EHT-LTF may be one of: 312.5 kHz if the information potion is 3.2 μs, 156.25 kHz if the information portion is 6.4 μs, or 78.125 kHz if the information portion is 12.8 μs. The information portion of the Data field of EHT MU PPDUis always 12.8 μs. Hence, a subcarrier spacing of the Data field is always 78.125 kHz corresponding to the duration of the information portion being 12.8 μs. When a 3.2 μs long or a 6.4 μs long EHT-LTF is used by a transmitting STA to transmit EHT MU PPDU, a receiving STA is required to interpolate the channel estimates to a subcarrier spacing resolution of 78.125 kHz to match the Data field subcarrier spacing.

6 FIG. 6 FIG. 600 600 600 602 1 602 2 602 3 602 4 602 1 602 2 602 3 602 4 602 1 602 3 602 1 602 4 600 430 illustrates an example universal signal (U-SIG) fieldwhich may be used in an extended range (ER) PPDU. U-SIG fieldmay be used in an ER preamble of the ER PPDU. As shown in, example U-SIG fieldincludes four OFDM symbols-,-,-, and-(each having a length of 4 microseconds). The coded bits of symbol-are identical to the coded bits of symbol-, and the coded bits of symbol-are identical to the coded bits of symbol-. For better frequency diversity, the encoded bits in symbols-and-may be interleaved, while the encoded bits in symbols-and-may not be interleaved. The constellation mapping of U-SIG fieldin an ER preamble may be the same as that of the HE-SIG-A field in an HE ER SU PPDU such as HE ER SU PPDU.

600 600 600 An EHT STA that receives an ER PPDU with an ER preamble including U-SIG fieldmay decode and interpret the version independent fields in U-SIG fieldthat may be introduced in IEEE 802.11 PHY clauses defined for 2.4, 5, and 6 GHz for EHT PHY onwards. Regardless of the value of a PHY version identifier field in U-SIG field, the EHT STA defers for the duration of the ER PPDU, reports the information from the version independent fields within an RXVECTOR, and terminates the reception of the ER PPDU.

7 FIG. 700 700 1 2 3 illustrates an example management framewhich may be used as an action frame. In an example, management frameincludes a MAC header, a variable length frame body, and a frame check sequence (FCS). The MAC header includes a frame control field, a duration field, an addressfield, an addressfield, an addressfield, a sequence control field, and an optional HT control field. The presence of the HT control field is determined by the setting of a +HTC subfield of the frame control field.

7 FIG. As shown in, when used as an action frame, the frame body of management frame includes an action field, vendor specific elements, management message integrity code element (MME), message integrity code (MIC), and an authenticated mesh peering exchange element.

The action field includes a category field and an action details field. The action field provides a mechanism for specifying extended management actions. The category field indicates a category of the action frame. The action details field contains the details of the action requested by the action frame.

The MME is present when management frame protection is negotiated, the frame is a group addressed robust Action frame, and (MBSS only) the category of the action frame does not support group addressed privacy as indicated by category values; otherwise not present.

The MIC element is present in a self-protected action frame if a shared pairwise master key (PMK) exists between the sender and recipient of this frame; otherwise not present.

The authenticated mesh peering exchange element is present in a self-protected action frame if a shared PMK exists between the sender and recipient of this frame; otherwise not present.

8 FIG. 8 FIG. 800 800 800 800 800 illustrates a Link Measurement Request frame. Link Measurement Request framemay be transmitted by a first STA to request a second STA to respond with a Link Measurement Report frame, which the first STA may use to measure link pathloss and to estimate link margin. In a non-directional multi-gigabit (DMG) BSS, Link Measurement Request frameis an Action frame. In a DMG BSS, Link Measurement Request frameis an Action frame or an Action No Ack frame. As shown in, Link Measurement Request frameincludes a Category field, a Radio Measurement Action field, a Dialog Token field, a Transmit Power Used field, a Max Transmit Power field, and an optional Extended Link Measurement field.

800 800 The Category field indicates a category of Link Measurement Request frame. In an implementation, the Category field is set to a value (e.g., 5) that identifies the category of Link Measurement Request frameas a Radio Measurement Action frame.

800 800 The Radio Measurement Action field indicates an action frame format of Link Measurement Request framefrom among a plurality action frame formats defined for radio measurement purposes. In an implementation, the Radio Measurement Action field is set to a value (e.g., 2) that identifies the action frame format of Link Measurement Request frameas a Link Measurement Request frame.

800 800 The Dialog Token field is set to a nonzero value chosen by the first STA transmitting Link Measurement Request frame. The value of the Dialog Token field identifies a dialog comprising Link Measurement Request frameand a corresponding Link Measurement Report frame. The value of the Dialog Token field allows a STA to group management frames sent or received at different times as part of the same dialog.

800 800 800 The Transmit Power Used field is set to a transmit power used to transmit Link Measurement Request frame. The Transmit Power Used field indicates the actual power used as measured at the antenna connector, in units of dBm, by the first STA when transmitting Link Measurement Request frame. The value of the Transmit Power Used field is determined any time prior to sending Link Measurement Request frameand has a tolerance of ±5 dB.

The Max Transmit Power field provides an upper limit on the transmit power as measured at an antenna connector to be used by the first STA on a current channel. The value of the Max Transmit Power field is set to the minimum of the maximum powers at which the first STA is permitted to transmit on the current channel by device capability, policy, and regulatory authority.

The Extended Link Measurement field is optionally present. When present, the Extended Link Measurement field contains an Extended Link Measurement element. The Extended Link Measurement element includes further information used to solicit a link measurement report.

9 FIG. 900 900 900 900 illustrates an example trigger frame. Trigger framemay correspond to a basic trigger frame as defined in the existing IEEE 802.11ax standard amendment. Trigger framemay be used by an AP to allocate resources for and solicit one or more trigger-based (TB) PPDU transmissions from one or more STAs. Trigger framemay also carry other information required by a responding STA to transmit a TB PPDU to the AP.

9 FIG. 900 As shown in, trigger frameincludes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User Info List field, a Padding field, and an FCS field.

The Frame Control field includes the following subfields: protocol version, type, subtype, To DS, From DS, more fragments, retry, power management, more data, protected frame, and +HTC.

The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the Duration field carries an association identifier (AID) of the STA that transmitted the frame in the 16 least significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1. In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV).

900 900 900 The RA field is the address of the STA that is intended to receive the incoming transmission from the transmitting station. The TA field is the address of the STA transmitting trigger frameif trigger frameis addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if the trigger frameis addressed to STAs from at least two different BSSs of the multiple BSSID set.

1000 900 900 900 The Common Info field may have a format as illustrated by common info fielddescribed further below. The common info field specifies a trigger frame type of trigger frame, a transmit power of trigger framein dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame. The trigger frame type of a trigger frame used by an AP to receive QoS data using UL MU operation is referred to as a basic trigger frame.

900 900 The User List Info field contains a User Info field per STA addressed in trigger frame. The per STA User Info field includes, among others, an AID subfield, an RU Allocation subfield, a Spatial Stream (SS) Allocation subfield, a modulation and coding scheme (MCS) subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame, and a Trigger Dependent User Info subfield. The Trigger Dependent User Info subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC sets the minimum priority AC traffic that can be sent by a participating STA. The AP determines the list of participating STAs, along with the BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and maximum duration of the TB PPDU per participating STA.

900 The Padding field is optionally present in trigger frameto extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIFS (short interframe spacing) after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1 s.

The FCS field is used by a STA to validate a received frame and to interpret certain fields from the MAC headers of a frame.

10 FIG. 10 FIG. 1000 1000 900 1000 illustrates an example Common Info field. Common Info fieldmay be similar to the Common Info field of trigger frameor an MU-RTS trigger frame, for example. As shown in, Common Info fieldmay include a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS required subfield, a UL BW subfield, a GI and HE/EHT-LTF Type/Triggered TXS Mode subfield, a first Reserved subfield, a Number of HE/EHT-LTF Symbols subfield, a second Reserved subfield, an LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a third Reserved subfield, an HE/EHT P160 subfield, a Special User Info Field Flag subfield, an EHT Reserved subfield, a fourth Reserved subfield, and a Trigger Dependent Common Info subfield. The Trigger Type subfield, UL Length subfield, More TF subfield, CS required subfield, UL BW subfield, GI and HE-LTF Type/Triggered TXS Mode subfield, first Reserved subfield, Number of HE/EHT-LTF Symbols subfield, second Reserved subfield, LDPC Extra Symbol Segment subfield, AP Tx Power subfield, Pre-FEC Padding Factor subfield, PE Disambiguity subfield, UL Spatial Reuse subfield, third Reserved subfield, HE/EHT P160 subfield, Special User Info Field Flag subfield, EHT Reserved subfield, fourth Reserved subfield, and Trigger Dependent Common Info subfield may have the same content and interpretation as corresponding subfields of an EHT variant Common Info field defined in the IEEE 802.11be draft amendment (“IEEE P802.11be/D3.1, March 2023”).

11 FIG. 11 FIG. 1100 1100 1102 1104 1 1104 8 illustrates an exampleusing a TB PPDU. As shown in, exampleincludes an APand a plurality of STAs-to-.

1102 1110 1104 1 1104 8 1104 1 1104 8 1104 1 1104 8 1110 1120 1120 1104 1140 1150 1120 1120 1100 1120 1140 1 1140 8 1102 1120 1130 11 FIG. In an example, APmay transmit TFto STAs-to-to solicit UL frames from STAs-to-. STAs-to-may respond simultaneously to TFby each transmitting a TB PPDU. In an example, TB PPDUmay have an 80 MHz bandwidth. As shown in, a STAmay duplicate four times over frequency each of the fields L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-STF to fill out the 80 MHz bandwidth. EHT-LTFsand a data fieldof PPDUmay fill out the entire 80 MHz bandwidth and are not duplicated over frequency. The number of EHT-LTFs transmitted by the STA (in time) is based on the maximum number of spatial streams across all RUs contained in the TB PPDU. In example, TB PPDUincludes eight EHT-LTFs-to-. APmay acknowledge TB PPDUby transmitting a multi-user block acknowledgment frame M-BA.

1120 1104 1 1104 8 1110 1104 1 1104 8 1102 1120 As TB PPDUstransmitted by STAs-to-are transmitted simultaneously in response to TF, precorrection of time, frequency, sampling clock, and power (in the case of a High Efficiency (HE) TB PPDU or extremely high throughput (EHT) TB PPDU) by STAs-to-may be necessary to mitigate synchronization and interference issues at AP. Specifically, frequency and sampling clock precorrections are needed to prevent inter-carrier interference. Power precorrection is necessary to control interference between TB PPDUs.

1110 1104 1 1104 8 1120 1120 In an implementation, TFincludes in a User Info field an uplink (UL) Target Receive Power subfield that indicates whether a STA among STAs-to-is to transmit TB PPDUat a maximum transmit power. The maximum transmit power may correspond to the STA's maximum transmit power for the assigned HE-MCS. The STA transmits TB PPDUat the maximum transmit power when the UL Target Receive Power subfield indicates that the maximum transmit power is to be used. Otherwise, the STA calculates the transmit power,

1120 of TB PPDUfor the assigned HE-MCS using the equation:

DL pwr 1110 1120 where PLis the downlink pathloss and TargetRxis the expected receive signal power, in units of dBm, as indicated by the UL Target Receive Power subfield in the User Info field of TF. If the STA applies beamforming to TB PPDU, the STA may take into account the beamforming gain when calculating the transmit power.

DL In an implementation, the STA computes PLusing the equation:

where

1110 1110 pwr pwr DL is the AP's transmit power, in units of dBm/20 MHz, as indicated by an AP Tx Power subfield of a Common Info field of TFand Rxis the receive signal power, in units of dBm/20 MHz, of TFat an antenna connector of the STA. Rxmay be an average of the receive signal power over the antennas on which the average PLis being computed.

1100 1110 1120 1110 Due to the finite accuracy of clock generating circuits of an AP and a STA, an AP and an associated STA tuned to the same carrier frequency may have errors in their generated carrier frequencies in reference to the ideal carrier frequency. When an AP receives a TB PPDU as in example, the AP may observe a baseband signal whose center frequency has an offset (i.e. carrier frequency offset or CFO) from the DC subcarrier. Similarly, an AP receiving the symbols of a TB PPDU sampled using its own clock may observe that the TB PPDU signal is generated at a clock offset (i.e. symbol clock offset or SCO) from its own sampling clock. Both SCO and CFO may result in receive errors when not properly mitigated. In order to limit the effects of CFO and SCO, a STA compensates for carrier frequency offset (CFO) error and symbol clock error with respect to TFwhen TB PPDUis a TB PPDU or a non-HT or non-HT duplicate PPDU with the TXVECTOR parameter TRIGGER RESPONDING set to true. After compensation, the absolute value of residual CFO error with respect to TFshall not exceed the following levels when measured at the 10% point of a complementary cumulative distribution function (CCDF) of CFO errors in Additive White Gaussian Noise (AWGN) at a received power of −60 dBm in the primary 20 MHz channel: 350 Hz for the data subcarriers of a TB PPDU; 2 kHz for a non-HT PPDU or non-HT duplicate PPDU. The residual CFO error measurement on an HE TB PPDU shall be made after the HE-SIG-A field. The residual CFO error measurement on an EHT TB PPDU shall be made after the U-SIG field. The residual CFO error measurement on a non-HT or non-HT duplicate PPDU shall be made after the L-STF field. The symbol clock error shall be compensated by the same ppm amount as the CFO error.

12 FIG. 3 5 FIGS.- 12 FIG. 310 10 illustrates the L-STF and the L-LTF. The L-STF and the L-LTF are part of a non-HT (or legacy) preamble of a non-HT PPDU as illustrated by non-HT PPDU. Additionally, as shown in, the legacy preamble is prepended to an HT mixed mode PPDU, a VHT PPDU, HE PPDUs, and EHT PPDUs. As shown in, the L-STF and the L-LTF each has a duration of 8 microseconds. The L-STF includes ten OFDM symbols called Short Training Symbols (STS). The L-STF is formed by the repetition of ten short symbols, SI to S, of 16 samples each. The L-STF may be used by a receiver for packet detection, automatic gain control (AGC), and coarse acquisition and frequency synchronization. The L-LTF includes a cyclic prefix (CP) of 1.6 microseconds and two identical symbols Long Training Symbols (LTS) L1 and L2 of 3.2 microseconds each. The CP of the L-LTF is twice as long as the CP of other symbols. The L-LTF may be used by a receiver for channel estimation and fine frequency offset correction.

13 FIG. 1300 1300 1300 illustrates an example extended/enhanced long range (ELR) PPDU. ELR PPDUis proposed to allow a STA to increase its transmission range. For example, a common problem in existing Wi-Fi environments is the asymmetry between the downlink transmission range of an AP and the uplink transmission range of a STA associated with the AP. When the STA is an edge STA (i.e., located at the edge of the AP's transmission range), the asymmetry results in the STA successfully receiving PPDUs from the AP but being unable to communicate with the AP. ELR PPDUmay reduce this downlink/uplink transmission range asymmetry by enabling the STA to increase its uplink transmission range to successfully reach the AP.

13 FIG. 14 FIG. 1300 1302 1304 1306 1302 1300 1302 1300 1302 1302 1302 1302 1300 1302 1302 1400 1300 1300 1300 1300 1300 As shown in, ELR PPDUincludes a legacy preamble, an ELR preamble, and an ELR data portion. Legacy preambleenables backward compatibility of ELR PPDU. Specifically, legacy preambleallows legacy IEEE 802.11 to detect ELR PPDU. Legacy preamblemay take various formats. For example, according to a first option, legacy preamblemay include an L-STF, an L-LTF, and an L-SIG. According to a second option, legacy preamblemay further include an RL-SIG after the L-SIG. The presence of the RL-SIG in legacy preambleincreases the range of ELR PPDUwhen received by a legacy IEEE 802.11 STA. In a third option, legacy preamblefurther includes one or more U-SIG fields, after the L-SIG and the RL-SIG. For example, legacy preamblemay be as illustrated by legacy preamblein. The one or more U-SIG fields provide U-SIG information that is used by a STA receiving ELR PPDU. For example, the one or more U-SIG fields may indicate a TXOP duration associated with ELR PPDU, a BSS Color associated with the STA transmitting ELR PPDU, a bandwidth associated with ELR PPDU, an UL/DL indication, and a PHY version of ELR PPDU.

1304 1300 1300 1300 1306 1300 ELR preamblemay include an ELR-STF, an ELR-LTF, and an ELR-SIG. Similar to the L-STF, the ELR-STF may be used by a receiver (e.g. an AP) of an ELR PPDUto synchronize with the carrier frequency and frame timing of the transmitter of the ELR PPDU(e.g. an edge STA) and to adjust the receiver signal gain. The L-LTF may be used by the receiver (e.g. an AP) of an ELR PPDUto estimate channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in both the ELR-SIG and ELR data portionof ELR PPDU.

2 1302 1304 The ELR-STF may be a longer version of L-STF to support longer range synchronization compared to L-STF. Similarly, ELR-LTF may be a longer version of L-LTF to support higher robustness when estimating the channel coefficients from the edge STA to the AP. The ELR-LTF may also include a higher number of symbol repetitions compared to the L-STF (e.g.,). It is noted that due to legacy preamble, ELR preamblemay be designed with a higher degree of flexibility without sacrificing backward compatibility.

1300 1300 1302 1300 1302 1304 1300 Due to the value of the U-SIG information to a legacy STA that receives ELR PPDU, it is desirable that ELR PPDUinclude the one or more U-SIG fields in legacy preamble. For example, including the U-SIG fields can enable an edge STA to communicate the BSS Color and TXOP duration associated with ELR PPDUfor added protection from OBSS transmissions. Including the U-SIG increases the overhead due to the legacy preamble. Additionally, to increase the transmission range, longer ELR-STF and ELR-LTF may be needed in ELR preamble. These, however, increase the size of ELR PPDUand the overhead associated with its transmission.

Embodiments of the present disclosure, as further described below, address this problem of existing technologies. In an aspect, an ELR PPDU is proposed. The proposed ELR PPDU reuses portions of the legacy preamble as portions of the ELR preamble, thereby significantly reducing the size of the ELR PPDU. In an embodiment, the L-LTF of the legacy preamble is reused as an ELR-STF of the ELR preamble. In an embodiment, to enable this reuse, a receiver of the ELR PPDU may transmit to a transmitter of the ELR PPDU a first frame that allows the transmitter to pre-compensate a carrier frequency offset of the ELR PPDU. In another embodiment, the first frame allows the transmitter to determine and apply a power offset to the ELR PPDU. The transmitter may transmit the ELR PPDU with a pre-compensated carrier frequency offset and/or with a pre-compensated transmit power. This eliminates the need of the receiver of the ELR PPDU to perform carrier frequency offset (CFO) estimation and/or automatic gain control (AGC) based on the ELR-STF. The receiver of the ELR PPDU may perform packet detection and/or coarse symbol timing based on the ELR-STF. In another aspect, the transmitter of the ELR PPDU may determine, based on the first frame, a received signal strength indicator (RSSI) of the first frame and a first carrier frequency offset of the first frame. The transmitter of the ELR PPDU may transmit the ELR PPDU with a second carrier frequency offset based on the first carrier frequency offset. In an embodiment, the second carrier frequency offset of the ELR PPDU is based on the first carrier frequency offset of the first frame based on the RSSI of the first frame being less than a threshold.

15 FIG. 15 FIG. 3 FIG. 4 FIG. 6 FIG. 1500 1500 1502 1504 1506 1502 illustrates an example ELR PPDUaccording to an embodiment. As shown in, example ELR PPDUincludes a legacy preamble, an ELR preamble, and an ELR data portion. Legacy preambleincludes an L-STF, an L-LTF, an L-SIG, an RL-SIG, and a U-SIG. The L-STF, L-LTF, and L-SIG are described inabove. The RL-SIG is described inabove. The U-SIG may comprise one or more U-SIG symbols. For example, the U-SIG may comprise two U-SIG symbols or four U-SIG symbols as described inabove.

1504 1508 1510 1512 1508 1510 1502 1502 1508 1500 1502 1500 1506 1500 1500 1500 1500 1500 15 FIG. ELR preambleincludes an ELR-STF, an ELR-LTF, and an ELR-SIG. As shown in, ELR-STFand ELR-LTFmay reuse the L-LTF, L-SIG, RL-SIG, and U-SIG of legacy preamble. In an embodiment, the L-LTF of legacy preambleprovides ELR-STF. That is, a receiver of ELR PPDUinterprets the L-LTF of legacy preambleas both an L-LTF and as an ELR-STF. For example, the receiver of ELR PPDUmay use the L-LTF to estimate channel coefficients to equalize a channel response (e.g., amplitude and phase distortion) in both the L-SIG and data portionof ELR PPDU. Additionally, the receiver of ELR PPDUmay use the L-LTF (as an ELR-STF) for packet detection, AGC, coarse symbol timing, and coarse CFO estimation. For example, if the receiver of ELR PPDUfails to detect ELR PPDUby searching one of the 10 STS of the L-STF due to a low signal-to-noise ratio (SNR), the receiver may successfully detect one of the two Long Training Symbols (LTS) in the L-STF of ELR PPDU.

1502 1510 1512 1512 1500 In an embodiment, one or more of the L-LTF, L-SIG, RL-SIG, and U-SIG of legacy preamblemay provide ELR-LTF. ELR-SIGmay include indications per STA of resource unit (RU) allocations. A STA may use the indications in the ELR-SIGto locate its payload in ELR PPDU.

16 FIG. 16 FIG. 1600 1500 1600 1602 1604 1602 1604 1602 1604 illustrates an examplethat highlights a potential problem that may arise using example ELR PPDUdescribed above. As shown in, exampleincludes a STAand a STA. In an example, STAmay be an AP STA, and STAmay be a non-AP STA, or vice versa. In another example, STAsandmay be AP STAs or non-AP STAs.

1600 1604 1606 1602 1606 1500 1606 1604 1606 1604 1606 1606 1604 1604 1604 1606 1604 1606 1604 1606 1606 1602 11 FIG. In example, STAtransmits a PPDUto STA. PPDUmay be an ELR PPDU such as ELR PPDU. PPDUmay carry a frame, such as a control frame, a management frame, or a data frame, for example. In an example, STAmay transmit PPDUusing enhanced distributed channel access (EDCA). In this example, STAmay transmit PPDUas an SU PPDU (e.g. HE SU PPDU, HE ER SU PPDU) or an MU PPDU (e.g. EHT MU PPDU or HE MU PPDU). In an example, in transmitting PPDU, STAmay use a maximum transmit power of STAfor an MCS used by STAto transmit PPDU. In another example, when STAtransmits PPDUin response to a triggering frame, STAmay determine a transmit power for PPDU, as described above with respect to, based on a downlink pathloss and an expected receive signal power of PPDUat STA.

1600 1602 1606 1602 1606 1602 1606 1602 1606 1602 1606 1606 1602 1606 1602 1606 In example, STAmay receive PPDUwith a receive signal power that does not allow STAto detect/decode the L-STF of the legacy preamble of PPDU. As described above, the L-STF is used by a receiver to perform packet detection, AGC, coarse symbol timing, and coarse CFO estimation. In an implementation, STAmay be configured, when failing to detect/decode the L-STF, to use the ELR-STF of the ELR preamble of PPDUto perform the receiver functions that are performed based on the L-STF. In another implementation, STAmay be configured, when failing to detect/decode the L-STF, to use the L-LTF of the legacy preamble of PPDUto perform the receiver functions that are performed based on the L-STF. STAmay be configured to do so in order to reduce the latency of decoding PPDUby not waiting for the ELR-STF (which is only available after the L-LTF, L-SIG, RL-SIG, and U-SIG symbols have been received). As the L-LTF serves an ELR-STF (or L-STF) in PPDU, STAmay thus need to perform packet detection, AGC, coarse symbol timing, and coarse CFO estimation based on the L-LTF of the legacy preamble of PPDU. However, as the L-LTF has a maximum of two symbol repetitions, the L-LTF may not be used for AGC. Further, with a subcarrier spacing of only 312.5 KHz, a coarse CFO estimation performed based on the L-LTF may be up to four times worse than a coarse CFO estimation performed based on the L-STF. STAmay thus fail to receive PPDU.

1500 In embodiments further described below, the STA transmitting an ELR PPDU such as ELR PPDUmay pre-compensate a transmit power and/or a carrier frequency offset of the ELR PPDU. This eliminates the need of the receiver of the ELR PPDU to perform CFO estimation and/or AGC based on the ELR-STF (provided by the L-LTF). The receiver of the ELR PPDU may perform packet detection and/or coarse symbol timing based on the ELR-STF. With the ELR PPDU pre-compensated for carrier frequency offset and transmit power, the receiver may successfully receive the ELR PPDU based on detecting the ELR-STF.

17 FIG. 17 FIG. 1700 1700 1702 1704 1702 1704 1702 1704 illustrates an exampleof a procedure using an ELR PPDU according to an embodiment. As shown in, exampleincludes a STAand a STA. In an example, STAmay be an AP STA, and STAmay be a non-AP STA, or vice versa. In another example, STAsandmay be AP STAs or non-AP STAs.

1700 1702 1704 1708 1704 1704 1704 1708 1500 In example, STAmay determine that STAis to use a first mode to transmit a PPDUto STA. The first mode may comprise an ELR operation mode. In an embodiment, STAusing the first mode comprises STAusing a first format for PPDU. The first format may be an ELR PPDU format such as that of ELR PPDU. Specifically, the ELR PPDU format may include a legacy preamble and an ELR preamble and may reuse an L-LTF of the legacy preamble as an ELR-STF of the ELR preamble.

1702 1704 1706 1704 1708 1702 1704 1708 1702 1702 1706 1708 1704 1702 1706 1702 1706 1704 1702 1706 1708 1704 1708 1706 1704 1708 1706 In an example, STAmay transmit to STAa framewith an indication for STAto use the first mode to transmit PPDUto STA(or an indication that STAis permitted to use the first mode to transmit PPDUto STAor an indication that STAenables reception of PPDUs using the first mode (e.g., ELR PPDUs)). In an embodiment, frameincludes an ELR field that includes the indication. In an implementation, PPDUmay be the next PPDU that STAtransmits to STAafter receiving frame. For example, when STAis an AP STA, framemay be a beacon frame or an action frame that indicates to STAto use the first mode to transmit the next PPDU to STA. In another implementation, framemay be a triggering frame for PPDU, and STAmay transmit PPDUin response to frame. For example, STAmay transmit PPDUa SIFS after receiving frame.

1708 1704 1708 1702 1702 1704 1708 1704 1708 1704 1708 1702 1708 1708 In an embodiment, based on the indication to use the first mode to transmit PPDU(or the indication that STAis permitted to use the first mode to transmit PPDUto STAor the indication that STAenables reception of PPDUs using the first mode), STAtransmits PPDUusing the first mode. That is, STAuses the first format for PPDU. Additionally, based on the indication, STAmay be configured to pre-compensate PPDUfor carrier frequency offset and/or transmit power to eliminate the need for STAto perform CFO estimation and/or AGC based on the ELR-STF of PPDU, provided by the L-LTF of the legacy preamble of PPDU.

1704 1706 1706 1706 1704 1704 1706 1706 1706 1704 In an embodiment, STAmay be configured determine a first carrier frequency offset of frame. The first carrier frequency offset of framemay correspond to a difference between a first carrier frequency of frameand a second carrier frequency of a local oscillator of STA. In an embodiment, STAmay be further configured to determine a first symbol clock offset (or symbol clock error) of frame. The first symbol clock offset of framemay correspond to a difference between a first symbol clock value measured based on frameand a second symbol clock value based on a reference symbol clock at STA.

1704 1708 1706 1704 1708 1708 1706 1702 1708 In an embodiment, STAmay pre-compensate PPDUfor carrier frequency offset based on the first carrier frequency offset of frame. In an implementation, STAmay process PPDUsuch that a second carrier frequency offset of PPDUis based on the first carrier frequency offset of frame. In an embodiment, the second carrier frequency offset may be set to a negative of the first carrier frequency offset. As such, the need for coarse CFO estimation by STAbased on PPDUmay be eliminated.

1704 1708 1708 1706 1702 1708 In another embodiment, STAmay pre-compensate PPDUfor symbol clock offset such that a second symbol clock offset of PPDUis based on the first symbol clock offset of frame. Coarse symbol timing by STAbased on PPDUmay thus be eliminated.

1704 1708 1704 1708 1704 1702 1704 1706 1706 1706 1702 800 1702 1706 1708 1708 1702 1706 1708 1704 1708 1708 1708 1708 8 FIG. In another embodiment, STAmay pre-compensate a transmit power of PPDU. In an implementation, STAmay determine a transmit power offset and may adjust a selected transmit power of PPDUbased on the transmit power offset. In an embodiment, STAmay determine a pathloss of a channel from STAandand may determine the transmit power offset based on the pathloss. In an implementation, framemay indicate a first transmit power used to transmit frame. For example, framemay comprise a transmit power field that indicates the first transmit power. The transmit power field may be set by STAas described inabove with respect to the Transmit Power Used field of Link Measurement Request frame. To determine the pathloss, STAmay subtract the first transmit power from an RSSI of frame. In an embodiment, the selected transmit power of PPDUmay be based on a target receive power of PPDUat STA. In an implementation, framemay indicate the target receive power of PPDU. STAmay determine the transmit power of PPDUbased on the target receive power of PPDUand the pathloss. In an embodiment, the transmit power of PPDUmay be equal to the target receive power of PPDUminus the pathloss.

1702 1708 1708 1702 1708 1708 1708 1702 1708 1702 1708 1702 1708 In an embodiment, STAmay detect PPDUusing the ELR-STF, provided by the L-LTF of the legacy preamble of PPDU. In another embodiment, STAmay determine a symbol timing of PPDUusing the ELR-STF, provided by the L-LTF of the legacy preamble of PPDU. With PPDUpre-compensated for carrier frequency offset and/or transmit power, STAmay not (or may not need to) perform coarse CFO estimation and/or AGC based on PPDU. As such, STAmay successfully receive PPDUeven if STAfails to detect the L-STF of the legacy preamble of PPDU.

18 FIG. 18 FIG. 1800 1800 1802 1804 1802 1804 1802 1804 illustrates an exampleof another procedure of using an ELR PPDU according to an embodiment. As shown in, exampleincludes a STAand a STA. In an example, STAmay be an AP STA, and STAmay be a non-AP STA, or vice versa. In another example, STAsandmay be AP STAs or non-AP STAs.

1800 1804 1808 1806 1804 1802 1804 1804 1808 1500 1806 1804 1802 1806 1802 1806 1804 1808 1806 In example, STAmay determine whether to transmit a PPDUusing the first mode based on an RSSI of a framereceived by STAfrom STA. As described above, the first mode may comprise an ELR operation mode. In an embodiment, STAusing the first mode comprises STAusing a first format for PPDU. The first format may be an ELR PPDU format such as that of ELR PPDU. Specifically, the ELR PPDU format may include a legacy preamble and an ELR preamble and may reuse an L-LTF of the legacy preamble as an ELR-STF of the ELR preamble. Framemay be any frame received by STAfrom STA. For example, framemay be a control frame, a management frame, or a data frame. In an embodiment, where STAis an AP STA, framemay be a beacon frame or an action frame. In an embodiment, STAmay determine to transmit PPDUusing the first mode when an RSSI of frameis below a threshold. In an implementation, the threshold is equal to −82 dBm.

1804 1808 1802 1804 1806 1806 1806 1802 800 1802 1806 1804 1808 8 FIG. In another implementation, STAmay determine whether to transmit PPDUusing the first mode based on a pathloss of a channel from STAto STA. In an embodiment, framemay indicate a first transmit power used to transmit frame. For example, framemay comprise a transmit power field that indicates the first transmit power. The transmit power field may be set by STAas described inabove with respect to the Transmit Power Used field of Link Measurement Request frame. To determine the pathloss, STAmay subtract the first transmit power from an RSSI of frame. In an embodiment, STAmay determine to transmit PPDUusing the first mode when the pathloss is above a threshold.

1808 1804 1808 1802 1808 1808 In an embodiment, based on determining to use the first mode for PPDU, STAmay be configured to pre-compensate PPDUfor carrier frequency offset and/or transmit power to eliminate the need for STAto perform CFO estimation and/or AGC based on the ELR-STF of PPDU, provided by the L-LTF of the legacy preamble of PPDU.

1804 1806 1806 1806 1804 1804 1806 1806 1806 1804 In an embodiment, STAmay be configured determine a first carrier frequency offset of frame. The first carrier frequency offset of framemay correspond to a difference between a first carrier frequency of frameand a second carrier frequency of a local oscillator of STA. In an embodiment, STAmay be further configured to determine a first symbol clock offset (or symbol clock error) of frame. The first symbol clock offset of framemay correspond to a difference between a first symbol clock value measured based on frameand a second symbol clock value based on a reference symbol clock at STA.

1804 1808 1806 1804 1808 1808 1806 1802 1808 In an embodiment, STAmay pre-compensate PPDUfor carrier frequency offset based on the first carrier frequency offset of frame. In an implementation, STAmay process PPDUsuch that a second carrier frequency offset of PPDUis based on the first carrier frequency offset of frame. In an embodiment, the second carrier frequency offset may be set to a negative of the first carrier frequency offset. As such, the need for coarse CFO estimation by STAbased on PPDUmay be eliminated.

1804 1808 1808 1806 1802 1808 In another embodiment, STAmay pre-compensate PPDUfor symbol clock offset such that a second symbol clock offset of PPDUis based on the first symbol clock offset of frame. Coarse symbol timing by STAbased on PPDUmay thus be eliminated.

1804 1808 1804 1808 1804 1802 1804 1806 1808 1804 1808 1808 1808 1808 In another embodiment, STAmay pre-compensate a transmit power of PPDU. In an implementation, STAmay determine a transmit power offset and may adjust a selected transmit power of PPDUbased on the transmit power offset. In an embodiment, STAmay determine the pathloss of the channel from STAandand may determine the transmit power offset based on the pathloss. In an implementation, framemay indicate the target receive power of PPDU. STAmay determine the transmit power of PPDUbased on the target receive power of PPDUand the pathloss. In an embodiment, the transmit power of PPDUmay be equal to the target receive power of PPDUminus the pathloss.

1802 1808 1808 1802 1808 1808 1808 1802 1808 1802 1808 1802 1808 In an embodiment, STAmay detect PPDUusing the ELR-STF, provided by the L-LTF of the legacy preamble of PPDU. In another embodiment, STAmay determine a symbol timing of PPDUusing the ELR-STF, provided by the L-LTF of the legacy preamble of PPDU. With PPDUpre-compensated for carrier frequency offset and/or transmit power, STAmay not (or may not need to) perform coarse CFO estimation and/or AGC based on PPDU. As such, STAmay successfully receive PPDUeven if STAfails to detect the L-STF of the legacy preamble of PPDU.

19 FIG. 19 FIG. 8 FIG. 1900 1900 1706 1900 800 illustrates an example ELR fieldthat may be used according to embodiments. For example, example ELR fieldmay be carried in a first frame, such as framedescribed above. As shown in, example ELR fieldincludes an ELR mode field, a Transmit Power Used field, and a Target Receive Power field. The ELR mode field indicates whether a receiver of the first frame is to use the first mode to transmit a PPDU to the transmitter of the first frame. The Transmit Power Used field indicates a transmit power used by the transmitter of the first frame to transmit the first frame. The Transmit Power Used field may be set by the transmitter of the first frame as described inabove with respect to the Transmit Power Used field of Link Measurement Request frame. The Target Receive Power field indicates a target receive power of the PPDU at the transmitter of the first frame.

18 FIG. 1806 In another embodiment (not shown in), an example ELR field may include the Transmit Power Used field and the Target Receive Power field but may not include the ELR mode field. The ELR field may be carried in a first frame, such as framedescribed above.

20 FIG. 20 FIG. 2000 2000 1704 1804 2000 2002 2004 illustrates an example processaccording to an embodiment. Example processmay be performed by a first STA, such as STAor STA, for example. The first STA may be an AP STA or a non-AP STA. As shown in, processmay include stepsand.

2002 Stepincludes receiving, by the first STA from a second STA, a first frame. The second STA may be an AP STA or a non-AP STA. In an embodiment, the second STA may be an AP STA, and the first frame may be a beacon frame or an action frame.

1500 600 In an embodiment, the first frame comprises an indication for the first STA to use a first mode to transmit a PPDU to the second STA (or an indication that the first STA is permitted to use the first mode to transmit a PPDU the second STA or an indication that first STA enables reception of PPDUs using the first mode (e.g., ELR PPDUs)). In an embodiment, the first mode comprises an ELR operation mode. In an embodiment, the first frame comprises an ELR field, and the ELR field comprises the indication. In an embodiment, the first STA using the first mode comprises the first STA using a first format for the PPDU. The first format may be an ELR PPDU format. For example, the first format may be the format of ELR PPDUdescribed above. In an embodiment, the first format comprises an L-STF, an L-LTF, an L-SIG, an RL-SIG, and/or a U-SIG field. The U-SIG field may comprise a plurality of OFDM symbols. For example, the U-SIG field may comprise two OFDM symbols (U-SIG1, U-SIG2) or four OFDM symbols as illustrated by example U-SIG field. In an embodiment, the first format comprises a legacy preamble, an ELR preamble, and a data portion. The ELR preamble may reuse fields of the legacy preamble. For example, an ELR-STF of the ELR preamble may be provided an L-LTF of the legacy preamble.

2004 Stepincludes transmitting, by the first STA to the second STA, a PPDU. In an embodiment, a second carrier frequency offset of the PPDU is based on a first carrier frequency offset of the first frame. In another embodiment, based on the first frame (e.g., comprising the indication), a second carrier frequency offset of the PPDU is based on a first carrier frequency offset of the first frame. In an embodiment, the second carrier frequency offset of the PPDU is a negative of the first carrier frequency offset of the first frame. In an embodiment, the second carrier frequency offset of the PPDU is based on the first carrier frequency offset of the first frame based on the first frame indicating the first mode. In another embodiment, the second carrier frequency offset of the PPDU is based on the first carrier frequency offset of the first frame based on an RSSI of the first frame being below a threshold. In an embodiment, the threshold is equal to −82 dBm. In a further embodiment, the second carrier frequency offset of the PPDU is based on the first carrier frequency offset of the first frame based on a determined pathloss of a channel from the second STA to the first STA being above a threshold. In an embodiment, the first STA determines the pathloss based on the RSSI of the first frame and a first transmit power used by the second STA to transmit the first frame. In an embodiment, the first frame indicates the first transmit power. For example, the first frame may comprise a transmit power field that indicates the first transmit power. In an embodiment, the first STA determines the pathloss by subtracting the subtracting the first transmit power from the RSSI of the first frame. In an embodiment, the first STA pre-compensates the PPDU for carrier frequency offset using the second carrier frequency offset.

2004 2004 In an embodiment, transmitting the PPDU in stepfurther comprises pre-compensating a transmit power of the PPDU based on the first frame. In an embodiment, the first STA pre-compensates the transmit power of the PPDU based on the first frame indicating the first mode, the RSSI of the first frame being below a threshold, or the determined pathloss of the channel from the second STA to the first STA being above a threshold. In an embodiment, pre-compensating the transmit power of the PPDU comprises determining, by the first STA, a transmit power offset of the PPDU based on the pathloss. In an embodiment, transmitting the PPDU in stepcomprises transmitting the PPDU with a second transmit power, where the second transmit power is based on a target receive power of the PPDU minus the pathloss. In an embodiment, the first frame indicates the target receive power of the PPDU.

2000 In an embodiment, processmay further comprise determining, by the first STA, a first symbol clock offset of the first frame and setting a second symbol clock offset of the PPDU based on the first symbol clock offset of the first frame. In an embodiment, the first STA sets the second clock offset of the PPDU based on the first symbol clock offset of the first frame, based on the first frame indicating the first mode, the RSSI of the first frame being below a threshold, or the determined pathloss of the channel from the second STA to the first STA being above a threshold.

2004 In an embodiment, the transmitting of the PPDU in stepcomprises transmitting the PPDU during a transmission opportunity (TXOP) obtained by the first STA.

21 FIG. 21 FIG. 2100 2100 1702 1802 2100 2102 2104 illustrates another example processaccording to an embodiment. Example processmay be performed by a first STA, such as STAor STA, for example. The first STA may be an AP STA or a non-AP STA. As shown in, processmay include stepsand.

2102 1500 600 Stepincludes transmitting, by the first STA to a second STA, a first frame, where the first frame comprises an indication for the second STA to use a first mode to transmit a PPDU to the first STA (or the indication that the second is permitted to use the first mode to transmit a PPDU to the first STA or the indication that the first STA enables reception of PPDUs using the first mode (e.g., ELR PPDUs)). In an embodiment, the first STA may be an AP STA, and the first frame may be a beacon frame or an action frame. In an embodiment, the first mode comprises an ELR operation mode. In an embodiment, the first frame comprises an ELR field, and the ELR field comprises the indication. In an embodiment, the second STA using the first mode comprises the second STA using a first format for the PPDU. The first format may be an ELR PPDU format. For example, the first format may be the format of ELR PPDUdescribed above. In an embodiment, the first format comprises an L-STF, an L-LTF, an L-SIG, an RL-SIG, and a U-SIG field. The U-SIG field may comprise a plurality of OFDM symbols. For example, the U-SIG field may comprise two OFDM symbols (U-SIG1, U-SIG2) or four OFDM symbols as illustrated by example U-SIG field. In an embodiment, the first format comprises a legacy preamble, an ELR preamble, and a data portion. The ELR preamble may reuse fields of the legacy preamble. For example, an ELR-STF of the ELR preamble may be provided an L-LTF of the legacy preamble.

2104 Stepincludes receiving, by the first STA from the second STA, the PPDU. In an embodiment, a first carrier frequency offset of the PPDU is based on a second carrier frequency offset of the first frame. In an embodiment, based on the indication, a first carrier frequency offset of the PPDU is based on a second carrier frequency offset of the first frame. In an embodiment, based on the indication, the second STA pre-compensates the PPDU for carrier frequency offset. In an embodiment, the first carrier frequency offset is a negative of the second carrier frequency offset.

2100 In an embodiment, processmay further comprise detecting, by the first STA, the PPDU using an L-LTF of the PPDU. In an embodiment, the L-LTF of the PPDU serves as an ELR-STF of the PPDU.

2100 In another embodiment, processmay further comprise determining, by the first STA and using the L-LTF, a symbol timing of the PPDU. In an embodiment, based on the indication, the second STA pre-compensates the PPDU for symbol clock offset. In an embodiment, a second symbol clock offset of the pre-compensated PPDU is based on a first symbol clock offset of the first frame.

In an embodiment, based on the indication, the second STA pre-compensates a transmit power of the PPDU. In an embodiment, the second STA pre-compensates the transmit power of the PPDU by determining a transmit power offset of the PPDU based on a pathloss of a channel from the first STA to the second STA. In an embodiment, the first frame indicates the target receive power of the PPDU, and the second STA determines the transmit power of the PPDU as the target receive power of the PPDU minus the pathloss.

2104 In an embodiment, the receiving of the PPDU in stepcomprises receiving the PPDU during a TXOP obtained by the second STA.